FirstToStrike said:
Oddworld: Abe's Exoddus -- This has got to be one of the most unique, awesome, and epic 2D side scrolling games ever made. It is sheer genius, although the learning curve is a bit high.
Holy meow. I'm glad I'm not the only one that remembers Oddworld. Not sure if Abe's Exodus is the one I played, but I most certainly miss that game.
Also:
Jade Cocoon -- Haven't played it in forever, so I can't tell you much about it, but a pretty awesome RPG, designed in part with Studio Ghibli, if you're a fan of them (and I am!)
The Legend of Dragoon -- The awesome of this game goes without saying. The only bad thing I have to say about it is that the voice acting in the last scene of the game was SO BAD that it quite nearly ruined the entire game for me. But the story is awesome, and it throws in some neat twists to traditional RPG gameplay.
Those Darn Final Fantasies -- Yes, those.
If you ask me, almost all of the good games for the PS1 were either RPGs or playformers. There's more, but none are coming to my mind at the moment, so I'm sure you can just refer to other posters. xD